Material-sensing light imaging, detection, and ranging (LIDAR) systems

ABSTRACT

Material-Sensing Light Imaging, Detection, And Ranging (LIDAR) systems optionally include a laser configured to generate a light pulse, a beam steerer configured to produce a polarization-adjusted light pulse emitted towards an object, at least one polarizer configured to polarize reflected, scattered, or emitted light returned from the object, and a processor configured to detect at least one material of the object based on an intensity and polarization of the polarized reflected, scattered or emitted light from the object. The beam steerer may include a kirigami nanocomposite. Methods are also provided, including, for example, generating a light pulse, adjusting a polarization of the light pulse to produce a polarization-adjusted light pulse emitted towards an object, polarizing reflected, scattered, or emitted light returned from the object, and detecting at least one material of the object based on an intensity and polarization of the polarized reflected, scattered or emitted light from the object.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase Application under 35 U.S.C.371 of International Application No. PCT/US2018/055708 filed on Oct. 12,2018, which claims the benefit of U.S. Provisional Application No.62/571,986 filed on Oct. 13, 2017. The entire disclosures of the aboveapplications are incorporated herein by reference.

GOVERNMENT SUPPORT

This invention was made with government support under 1240264 awarded bythe National Science Foundation. The Government has certain rights inthe present disclosure.

FIELD

The present disclosure relates to Light Imaging, Detection, And Ranging(LIDAR) systems and, more particularly, to materials-sensing LIDARsystems and methods for making and using the same.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

LIDAR is a surveying method that measures distance to an object byilluminating the object with a pulsed laser light, and measuring thereflected pulses with a sensor. Differences in laser return times andwavelengths can then be used to make digital 3D-representations of thedetected object. LIDAR may be used to produce high-resolution maps, withapplications in geodesy, geomatics, archaeology, geography, geology,geomorphology, seismology, forestry, atmospheric physics, laserguidance, airborne laser swath mapping (ALSM), and laser altimetry.LIDAR technology may also be used for the control and navigation ofautonomous cars.

A conventional LIDAR device may operate as follows. A laser sourceproduces a pulse of polarized or unpolarized light at a specificwavelength. When the light is first emitted, a time-of-flight sensorrecords the initial time. The time-of-flight is used to determine thetotal distance the light travels from source to detector by using thespeed at which light travels.

The emitted light is then “steered” in a given angle. This “steering”can also include the splitting of a light pulse into multiple pulsecomponents aimed at various angles. The steering angle(s) will changeover time in order to obtain a specific field of view for acomprehensive mapping of the environment. After it has been aimed, thelight may pass through linear polarization optics before and after theemission. These types of LIDARs are known as polarization LIDARs, andmay use polarization optics at a registration step.

Conventional LIDAR devices typically employ optical lenses that arebulky and expensive. Moreover, the optical lenses utilized inconventional LIDAR devices require extensive protective packaging due totheir sensitivity to moisture, which increases the weight, size, andcomplexity of the LIDAR devices in which they are employed. Onewell-known problem with implementation of LIDAR systems with rotationaloptics (e.g., the Velodyne-HDL64™ model) in autonomous vehicles androbots is their large size and high cost. The rotation of the entiredevice to steer laser beams reduces reliability, restrictsminiaturization, and increases energy consumption. LIDAR systems basedon solid-state beam steering address this problem, but theirimplementation is impeded by insufficient accuracy and range. Anotherissue is the performance of LIDARs and all the other sensors ininclement weather. Currently utilized laser beams with wavelengthsaround 900-940 nm can be strongly scattered by rain, fog, and snow, sothat their read-outs can become highly uncertain under such conditions.

In addition, conventional LIDAR devices and their appurtenant analysissystems have proven limited in their ability to accurately to performobject recognition. For example, LIDAR point clouds are known to bebased solely on a distance read-out from the laser source to the object.In this representation of the human world, a person resting on a benchand a statue of the same are identical. The problem is also true for asleeping baby and a similarly sized plastic doll lying next to it, orwhen attempting to distinguish a black car in the distance from thepavement. The burden of distinguishing these objects and deciphering thesurroundings is carried by the computational processing of these 3Dmaps.

Adequate classification of objects based on their geometries is not atrivial problem, requiring complex algorithms and large computationalpower, especially considering the highly dynamic nature of variousenvironments. Furthermore, typical LIDAR hardware makes adequate objectrecognition and classification even more difficult because the currentbeam steering methods cause clustering and banding of points in LIDARclouds, which results in ambiguous interpretation of 3D images and theirindividual points. Consequently, the geometry-based perception ofsurroundings demands high computational costs, large energy consumption,and long processing times.

Accordingly, improved LIDAR systems and methods are desired, especiallyLIDAR systems and methods providing an ability to identify the materialfrom which an object is formed.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In certain aspects, the present disclosure provides a system comprisinga laser configured to generate a light pulse, a beam steerer configuredto produce a polarization-adjusted light pulse emitted towards anobject, at least one polarizer configured to polarize reflected,scattered, or emitted light returned from the object, and a processorconfigured to detect at least one material of the object based on anintensity and polarization of the polarized reflected, scattered oremitted light from the object.

In one aspect, the beam steerer comprises a kirigami nanocomposite.

In one aspect, the at least one polarizer comprises a kirigaminanocomposite.

In one aspect, the processor is further configured to classify theobject based on the detected at least one material of the object.

In a further aspect, the processor is configured to classify the objectbased on the detected at least one material of the object by applying amachine-learning algorithm.

In a further aspect, the machine-learning algorithm comprises anartificial neural network algorithm.

In one aspect, the beam steerer is configured to adjust a polarizationof the light pulse to produce the polarization-adjusted light pulse.

In one aspect, the beam steerer is configured to adjust a polarizationof the light pulse by at least one of imparting a polarization to anunpolarized light pulse and changing a polarization of a polarized lightpulse.

In one aspect, the beam steerer is configured to adjust a polarizationof the light pulse by applying at least one of the following types ofpolarization: linear polarization, circular polarization, and ellipticalpolarization.

In a further aspect, applying linear polarization comprises applying atleast one of s-type linear polarization and p-type linear polarization.

In one aspect, the at least one polarizer is configured to polarize thereflected, scattered, or emitted light returned from the object byapplying at least one of the following types of polarization: linearpolarization, circular polarization, and elliptical polarization.

In a further aspect, the applying is applying linear polarization thatcomprises applying at least one of s-type linear polarization and p-typelinear polarization.

In one aspect, the at least one polarizer comprises a plurality ofpolarizers.

In one aspect, the system further comprises at least one polarizationdetector connected to the at least one polarizer and the processor,wherein the at least one polarization detector is configured to detectthe intensity of the polarized reflected, scattered or emitted lightfrom the object.

In a further aspect, the at least one polarization detector comprises aplurality of polarization detectors.

In a further aspect, the at least one polarization detector isconfigured to detect an angle of incidence associated with the polarizedreflected, scattered or emitted light from the object.

In a further aspect, the processor is further configured to detect theat least one material of the object based on the angle of incidenceassociated with the polarized reflected, scattered or emitted light fromthe object.

In yet other variations, the present disclosure provides a methodcomprising generating a light pulse, adjusting a polarization of thelight pulse to produce a polarization-adjusted light pulse emittedtowards an object, polarizing reflected, scattered, or emitted lightreturned from the object, and detecting at least one material of theobject based on an intensity and polarization of the polarizedreflected, scattered or emitted light from the object.

In one aspect, adjusting the polarization of the light pulse isperformed by a beam steerer comprising a kirigami nanocomposite.

In one aspect, the kirigami nanocomposite is manufactured via avacuum-assisted filtration (VAF) process.

In one aspect, the kirigami nanocomposite is manufactured via alayer-by-layer (LBL) deposition process.

In one aspect, the method further comprises classifying the object basedon the detected at least one material of the object.

In one aspect, classifying the object comprises classifying the objectby applying a machine-learning algorithm.

In one aspect, the machine-learning algorithm comprises an artificialneural network algorithm.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a functional diagram illustrating an M-LIDAR system accordingto certain aspects of the present disclosure;

FIGS. 2a-2b are scanning electron microscope (SEM) images ofnano-kirigami nanocomposite sheets configured for use in a M-LIDARsystem according to certain aspects of the present disclosure;

FIGS. 3a-3c are images depicting laser diffraction patters fromnano-kirigami-based graphene composites for various strain levels (0% inFIG. 3 a, 50% in FIG. 3b , and 100% in FIG. 3c ) according to certainaspects of the present disclosure;

FIGS. 4a-4d illustrate a representative simplified process formanufacturing nano-kirigami-based optical elements according to certainaspects of the present disclosure;

FIGS. 5a-5c illustrate a nano-kirigami nanocomposite optical elementfabricated on a wafer according to certain aspects of the presentdisclosure. FIG. 5a shows a photograph of a nano-kirigami nanocompositeoptical element, FIG. 5b shows an SEM image of the nano-kirigaminanocomposite optical element of FIG. 5a under 0% strain, while FIG. 5cillustrates a SEM image of the nano-kirigami nanocomposite opticalelement of FIG. 5a under 100% strain according to certain aspects of thepresent disclosure;

FIG. 6 illustrates a confusion matrix for MST using an artificialintelligence algorithm and polarization information according to certainaspects of the present disclosure;

FIG. 7 illustrates a confusion matrix for the detection of simulatedblack ice compared to other materials according to certain aspects ofthe present disclosure;

FIG. 8 illustrates one example of a black ice detection unitincorporating a M-LIDAR system according to certain aspects of thepresent disclosure;

FIG. 9 is a flowchart illustrating a method of performing objectclassification using an M-LIDAR system according to certain aspects ofthe present disclosure;

FIG. 10 is a schematic of a planar composite material having arepresentative plurality of kirigami cuts formed therein as a linearpattern; and

FIG. 11 is a diagram illustrating an M-LIDAR system for mounting on avehicle according to certain aspects of the present disclosure.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific compositions, components, devices, and methods, to provide athorough understanding of embodiments of the present disclosure. It willbe apparent to those skilled in the art that specific details need notbe employed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a,” “an,” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, elements, compositions, steps, integers, operations, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof. Although the open-ended term “comprising,” is tobe understood as a non-restrictive term used to describe and claimvarious embodiments set forth herein, in certain aspects, the term mayalternatively be understood to instead be a more limiting andrestrictive term, such as “consisting of” or “consisting essentiallyof.” Thus, for any given embodiment reciting compositions, materials,components, elements, features, integers, operations, and/or processsteps, the present disclosure also specifically includes embodimentsconsisting of, or consisting essentially of, such recited compositions,materials, components, elements, features, integers, operations, and/orprocess steps. In the case of “consisting of,” the alternativeembodiment excludes any additional compositions, materials, components,elements, features, integers, operations, and/or process steps, while inthe case of “consisting essentially of,” any additional compositions,materials, components, elements, features, integers, operations, and/orprocess steps that materially affect the basic and novel characteristicsare excluded from such an embodiment, but any compositions, materials,components, elements, features, integers, operations, and/or processsteps that do not materially affect the basic and novel characteristicscan be included in the embodiment.

Any method steps, processes, and operations described herein are not tobe construed as necessarily requiring their performance in theparticular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed, unless otherwiseindicated.

When a component, element, or layer is referred to as being “on,”“engaged to,” “connected to,” or “coupled to” another element or layer,it may be directly on, engaged, connected or coupled to the othercomponent, element, or layer, or intervening elements or layers may bepresent. In contrast, when an element is referred to as being “directlyon,” “directly engaged to,” “directly connected to,” or “directlycoupled to” another element or layer, there may be no interveningelements or layers present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.). As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various steps, elements, components, regions, layers and/orsections, these steps, elements, components, regions, layers and/orsections should not be limited by these terms, unless otherwiseindicated. These terms may be only used to distinguish one step,element, component, region, layer or section from another step, element,component, region, layer or section. Terms such as “first,” “second,”and other numerical terms when used herein do not imply a sequence ororder unless clearly indicated by the context. Thus, a first step,element, component, region, layer or section discussed below could betermed a second step, element, component, region, layer or sectionwithout departing from the teachings of the example embodiments.

Spatially or temporally relative terms, such as “before,” “after,”“inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and thelike, may be used herein for ease of description to describe one elementor feature's relationship to another element(s) or feature(s) asillustrated in the figures. Spatially or temporally relative terms maybe intended to encompass different orientations of the device or systemin use or operation in addition to the orientation depicted in thefigures.

Throughout this disclosure, the numerical values represent approximatemeasures or limits to ranges to encompass minor deviations from thegiven values and embodiments having about the value mentioned as well asthose having exactly the value mentioned. Other than in the workingexamples provided at the end of the detailed description, all numericalvalues of parameters (e.g., of quantities or conditions) in thisspecification, including the appended claims, are to be understood asbeing modified in all instances by the term “about” whether or not“about” actually appears before the numerical value. “About” indicatesthat the stated numerical value allows some slight imprecision (withsome approach to exactness in the value; approximately or reasonablyclose to the value; nearly). If the imprecision provided by “about” isnot otherwise understood in the art with this ordinary meaning, then“about” as used herein indicates at least variations that may arise fromordinary methods of measuring and using such parameters. For example,“about” may comprise a variation of less than or equal to 5%, optionallyless than or equal to 4%, optionally less than or equal to 3%,optionally less than or equal to 2%, optionally less than or equal to1%, optionally less than or equal to 0.5%, and in certain aspects,optionally less than or equal to 0.1%.

In addition, disclosure of ranges includes disclosure of all values andfurther divided ranges within the entire range, including endpoints andsub-ranges given for the ranges.

Example embodiments will now be described more fully with reference tothe accompanying drawings.

The present disclosure provides LIDAR systems and methods configured todetect not only an object's distance, but also the object's materialcomposition. According to some examples, material compositionclassification may be achieved by virtue of polarization analysisprocessed using machine learning algorithms.

The optical elements of the system described herein may be configured tobring all of the light emitted from a light source (e.g., a laser) to aknown polarization state, such that the shift in polarization can beaccurately measured later on. This light then travels until it reachesan object interface (the object being composed of one or morematerials), at which point a portion of the light will be diffuselyreflected back.

This disclosure describes, among other things, a new method ofperception of surroundings by creating semantic maps of 3D space withthe addition of materials and surface texture (MST) classification ateach point of the LIDAR cloud. The MST classification inferred from thepolarization signature of the returned photons may reduce the ambiguityof 3D point clouds and facilitate the recognition of various objects(metal points, glass points, rough dielectric points, etc.). Thepolarization classification may precede the surface tangent planeestimation and, therefore, may pre-identify the objects by grouping thepoints with similar polarization signatures. LIDARs that are equippedwith MST classification will be referred to herein as M-LIDARs.

According to one example of the instant disclosure, the M-LIDARtechnology may be configured to be lightweight and conformable throughthe use of kirigami optics, rather than conventional, bulky optics, suchas near-infrared optics and the like. According to one example, theM-LIDAR systems and methods described herein may be used in thedetection of black ice for vehicles with different degree of automation.

Referring now to FIG. 1, a representative simplified M-LIDAR system 100is provided. The M-LIDAR system 100 may include a laser 102, a beamsteerer 106, a first polarizer 114, a second polarizer 116, a firstpolarization detector 122, a second polarization detector 124, and aprocessor 126. Although FIG. 1 illustrates first and second polarizers114, 116 and first and second polarization detectors 122, 124, accordingto some implementations, only a single polarizer (e.g., the firstpolarizer 114) and a single polarization detector (e.g., the firstpolarization detector 122) may be included as part of the system 100without departing from the teachings of the present disclosure.Furthermore, according to certain examples, more than two polarizersand/or more than two polarization detectors may be included as part ofthe system 100 without departing from the teachings herein.

For purposes of simplicity and illustration, throughout the remainder ofthis disclosure the first polarizer 114 will be treated as as-polarization linear polarizer 114. Similarly, for purposes ofsimplicity and illustration, the second polarizer 116 will be treated asa p-polarization linear polarizer 116. Further, the first polarizationdetector 122 will be treated as a p-polarization detector 122 and thesecond polarization detector will be treated as a s-polarizationdetector 124.

However, as will be appreciated by those having ordinary skill in theart, the polarizers 114, 116 may be configured for a variety ofdifferent types of polarization without deviating from the teachingsherein. For example, a given polarizer may be configured to performlinear polarization (e.g., s or p type linear polarization),right-circular polarization, left-circular polarization, ellipticalpolarization, or any other suitable type of polarization known in theart. Similarly, a given detector may be configured to detectlinearly-polarized light (e.g., s or p type linearly polarized light),right-circular polarized light, left-circular polarized light,elliptically-polarized light, or any other type of polarized light knownin the art. According to some examples, the polarization of a light beam(i.e., a combination of two or more light pulses) may be modulated frompulse to pulse to obtain additional information about one or moreobjects under consideration.

As discussed in additional detail below, the system 100 may beconfigured to detect one or more materials making up an object 110, andclassify the object 110 based, at least in part, on the detectedmaterials. According to some examples, the object classification may beperformed using one or more artificial intelligence algorithmsincluding, but not limited to, neural network-based artificialintelligence.

In operation, the system 100 may function as follows. The laser 102 maybe configured to generate (i.e., emit) one or more polarized orunpolarized light pulses, the one or more polarized or unpolarized lightpulses collectively forming a polarized/unpolarized light beam 104.According to the example shown in FIG. 1, each pulse includes ans-polarization component (represented by the dots along the beam 104 inFIG. 1) and a transverse p-polarization component (represented by thedouble-sided arrows running in a perpendicular direction through thebeam 104 in FIG. 1). Alternatively (and in conjunction with thepreceding discussion on different types of polarized light), the pulsesmay include, for example, left and right circularly polarized sequences,elliptically polarized sequences, any combination of the foregoing, orany other suitably polarized light sequences.

According to some examples, the laser 102 may be configured to generateanywhere from one, to over one million, pulses a second. Furthermore,according to some implementations, the laser 102 may constitute a 550nanometer (nm), 808 nm, 905 nm, or 1550 nm pulsed laser—or any othersuitable wavelength of laser—without deviating from the teachings of theinstant disclosure. For example, implementations for home robotics,autonomous vehicles, and machine vision may employ lasers havingeye-safe frequencies above 800 nm. For outdoor applications, light beamsin the water transparencies windows—around 900 nm to 1550 nm, forexample—may be suitably employed. According to some implementations,upon a given pulse being generated by the laser 102, the processor126—executing executable instructions—may record the initial time thatthe pulse is generated. This “time-of-flight” information may besubsequently utilized to calculate a distance to the object 110 by usingthe speed of light.

The beam 104 may be directed by the laser 102 through the beam steerer106. The beam steerer 106 may be configured to produce apolarization-adjusted light pulse. In certain aspects, a polarization ofeach polarized/unpolarized pulse of the polarized/unpolarized light beam104 is adjusted by the beam steerer 106. As used herein, adjusting apolarization may include imparting a polarization or changing apolarization. Thus, the beam steerer 106 may adjust a polarization ofeach polarized/unpolarized pulse of the polarized/unpolarized light beam104 to produce one or more linearly polarized light pulses (the linearlypolarized light pulses collectively forming a linearly polarized lightbeam 108). While the foregoing example contemplates linear polarization,the beam steerer 106 may, according to some examples, circularly (e.g.,left or right) or elliptically polarize the beam 104. According toanother example, the beam steerer 106 may not apply any polarization tothe beam at all. For example, if the beam 104 is already polarized as itenters the beam steerer 106, the beam steerer 106 may further modify theproperties of the polarization-adjusted light pulse produced (e.g.,split or modulate the pulses), but may not need to adjust the polarityof the previously polarized light pulse. Further still, according tosome examples, the beam steerer 106 may polarize a first pulse of a beamaccording to a first type of polarization and polarize a second pulse ofthe same beam according to a second, different type of polarization. Inaddition to, or as an alternative to, performing polarization of thebeam 104, the beam steerer 106 may also control the direction of anybeam (e.g., beam 108) emitted therefrom. Further still, the beam steerer106 may split a beam (e.g., beam 104) into several different beams,whereby one or more of the beams are emitted a defined angles, to steermultiple beams at a time. This concept is illustrated in FIG. 1 withregard to the many diverging arrows emanating from the beam steerer 106.

In addition, or alternatively, in some examples, the beam steerer 106may be configured to modulate the linearly polarized light beam 108. Inone example, the beam steerer 106 may include a kirigami nanocompositebeam steerer or the like. According to this example, and as discussed inadditional detail below, the beam steerer 106 may be configured tolinearly polarize and/or modulate the linearly polarized light beam 108by increasing or decreasing an amount of strain applied to the kirigaminanocomposite beam steerer.

Furthermore, according to one example, the beam steerer 106 may beconfigured to linearly polarize each unpolarized pulse of theunpolarized light beam 104 by linearly polarizing each unpolarized pulseof the unpolarized light beam 104 for p-polarization. This example isillustrated in FIG. 1 where it can be seen that the beam 104, afterpassing through the beam steerer 106, no longer includes anys-polarization components (i.e., “dot” components shown in beam 104 areabsent in linearly polarized light beam 108). In alternative aspects,the linearly polarized light beam 108 may instead be p-polarized.Further, in certain aspects, the beam steerer 106 may modify, control,and steer the linearly polarized light beam 108 emitted towards object110, as will be discussed further herein. The beam steerer 106 mayenable dynamic, wavelength-dependent beam steering and amplitudemodulation of electromagnetic waves.

Continuing with FIG. 1, the linearly polarized light beam 108 may bediffusively reflected off the object 110. One or more pulses of lightcollectively form a beam 112 that constitutes a reflected version of thelinearly polarized light beam 108. According to some examples, thereflected linearly polarized light beam 112 may have a differentpolarization than the linearly polarized light beam 108 (i.e., the beampre-reflection off of the object 110). This difference in status isillustrated by virtue of the beam 112 including both p-polarization ands-polarization components (reflected, respectively, by the dots anddouble-sided arrows along the path of the beam 112), whereas the beam108 only is shown to include p-polarization components. Further, theobject 110 may include any suitable object (or target) made up of one ormore different materials of which detection is desired. Althoughdiscussed above and in the sections that follow as being a reflected“linearly” polarized light beam 112, according to certain examples, thereflected beam 112 may be polarized in a variety of different ways,including circularly or elliptically, without deviating from theteachings herein.

The reflected linearly polarized light beam 112 diffusively reflectedoff, scattered off of, or otherwise emitted by the object 112 may passthrough the s-polarization linear polarizer 114 and/or thep-polarization linear polarizer 116 of the system 100. In certainaspects, respective portions of the reflected, scattered, or otherwiseemitted linearly polarized light beam 112 passes through both thes-polarization linear polarizer 114 and/or the p-polarization linearpolarizer 116 of the system 100. The s-polarization linear polarizer 114is configured to linearly polarize the one or more light pulses makingup the beam 112 for s-polarization to produce one or more reflecteds-polarization light pulses (the one or more reflected s-polarizationlight pulses collectively forming a reflected s-polarization light beam118). Similarly, the p-polarization linear polarizer 116 is configuredto linearly polarize the one or more light pulses making up the beam 112for p-polarization to produce one or more reflected p-polarization lightpulses (the one or more reflected p-polarization light pulsescollectively forming a reflected p-polarization light beam 120).According to some examples, the s-polarization linear polarizer 114and/or the p-polarization linear polarizer 116 may include a kirigaminanocomposite or the like, such as kirigami nanocomposites of the typesdiscussed above with regard to the beam steerer 106 and/or below withregard to FIGS. 4a-4d and 5a-5c . However, those having ordinary skillin the art will recognize that non-kirigami nanocomposites or otheroptic devices may be employed as part of the system 100, according tosome examples, without deviating from the teachings herein.

Similar arrangements of polarizers 114, 116 may be utilized, accordingto some examples, for the polarization of left and right circularlypolarized light or elliptically polarized light reflected, scattered orotherwise emitted off/from the object 110.

An s-polarization detector 122 may be configured to detect an intensityof each of the one or more reflected s-polarization light pulses formingthe reflected s-polarization light beam 118. In addition, according tosome implementations, the s-polarization detector 122 may be configuredto detect an angle of incidence associated with the reflecteds-polarization light beam 118. The detected intensity of the one or morereflected s-polarization light pulses forming the reflecteds-polarization light beam 118 and/or the detected angle of incidenceassociated with the reflected s-polarization light beam 118 may beutilized by the processor 126 to perform material type detection (using,for example, MST classification), as discussed in additional detailbelow.

Similarly, a p-polarization detector 124 may be configured to detect anintensity of each of the one or more reflected p-polarization lightpulses forming the reflected p-polarization light beam 120. In addition,according to some implementations, the p-polarization detector 124 maybe configured to detect an angle of incidence associated with thereflected p-polarization light beam 120. The detected intensity of theone or more reflected p-polarization light pulses forming the reflectedp-polarization light beam 120 and/or the detected angle of incidenceassociated with the reflected p-polarization light beam 120 may also beutilized by the processor 126 to perform material type detection, asdiscussed in additional detail below.

The processor 126 is configured to detect at least one material of theobject 110 based on (i) the detected intensities of the one or morelight pulses forming beams 118 and/or 120 and/or (ii) the detectedangles of incidence associated with the reflected s-polarization lightbeam 118 and/or the reflected p-polarization light beam 120. Morespecifically, according to some examples, the processor 126 isconfigured to apply machine-learning algorithms to detect the one ormore materials making up the object 110. As used herein, “applying amachine-learning learning algorithm” may include, but is not limited to,executing executable instructions stored in memory and accessible by theprocessor. In addition, according to one example, the specificmachine-learning algorithm used for material detection may include anartificial neural network. However, other machine-learning algorithmsknown in the art may be suitably employed without deviating from theteachings of the instant disclosure.

Furthermore, according to some examples, the processor 126 may beconfigured to classify the object 110 based on the detected material(s)of the object 110 by applying a machine-learning algorithm. Again, themachine learning algorithm used for object classification may include anartificial neural network. However, other machine-learning algorithmsknown in the art may be suitably employed without deviating from theteachings of the instant disclosure.

Before turning to FIG. 2, the following reflects an overview of theprocess for detecting the material(s) of an object utilizing a M-LIDARsystem, such as the system 100 shown in FIG. 1

As noted above, one aim of the instant disclosure is to enable thedetection of object materials and to reduce the data processingnecessary for modern LIDAR devices by obtaining more data at each pointin the point cloud. This additional polarization data, when combinedwith machine learning algorithms, enables material detection, whichsimplifies object recognition for a variety of applications including,but not limited to, autonomous vehicles, machine vision, medicalapplications (e.g., devices to assist the blind), and advanced robotics.

An M-LIDAR system according to example implementations of the instancedisclosure may operate as follows. The pair of detectors (e.g.,detectors 122, 124) with perpendicularly oriented linear polarizers(e.g., polarizers 114, 116) may be used to measure the return light(e.g., the one or more pulses of light constituting the reflectedversion of the linearly polarized light beam 112). Some of the diffuselybackscattered light (e.g., reflected light 112) may be directed at thedetectors (e.g., detectors 122, 124) and pass through the narrow bandinterference filters (e.g., linear polarizers 114, 116) placed in frontof each detector pair (e.g., detector pair 122/124). The narrow bandinterference filters may only allow a small range of wavelengths to passthrough (e.g., 1-2 nm), which may reduce undesired noise from ambientlighting or external sources.

According to other examples of the foregoing system, the system may beconfigured to detect, and perform machine-learning processing upon,circularly and/or elliptically polarized light reflected, scattered, orotherwise emitted by an object.

Due to this selectivity, an M-LIDAR system in accordance with thepresent disclosure (e.g., system 100) may be configured tosimultaneously measure multiple wavelengths, completely independently.The coherent light may then be polarized using, for example, aco-polarizer and/or cross-polarizer. The intensity of light may decreaseby some amount as it travels through the polarizers, depending on theshift in polarization upon reflecting off of the object (e.g., object110). Beam focusing optics (e.g., polarizers 114, 116) may direct thecoherent, polarized light (e.g., beams 118, 120) towards the detectionsurface (e.g., the surfaces of detectors 122, 124), and the angle fromwhich the returned light traveled (i.e., the angle(s) of incidence) canbe detected based on the location the light strikes on the detectionscreen.

Once the detectors identify light, the time-of-flight sensor (e.g., thetime of flight sensor implemented in the processor 126) may record thetravel time of that light pulse. Each light pulse may have its intensitymeasured for both the co-polarized and cross-polarized detectors, andthese two values in combination allow the polarization effects causedduring the reflection to be quantified.

Following this process, the following parameters may be detected: (i)initial angle(s) at which the beam was steered; (ii) angle(s) from whichthe backscattered light returns; (iii) the time-of-flight from emissionto detection; and (iv) the intensity at each detector.

Note that due to the detectors being at different locations, a singlepulse of light may take a slightly different amount of time to reacheach detector. By understanding the system geometry as well as therelationship between intensity and distance, this difference can becompensated for and the intensity at one detector precisely adjusted.The time-of-flight data may be used to determine the distance betweenthe source (e.g., the laser 102) and the object (e.g., the object 110),and—in conjunction with the initial and return angle—the specificlocation of that point in space, relative to the M-LIDAR system, can bedetermined. These compensated intensity values may contain informationindicative of the material off of which the light pulse reflected.Making use of these values, machine learning algorithms may providerobust and comprehensive material recognition capabilities.

The process described above of emitting a pulse of light, the lightdiffusely reflecting off an object, the reflected light being measuredby the detectors, and the location of the object relative to the sourcebeing determined may be repeated on the order of one to millions oftimes per second. A point is generated each time, and these points aremapped onto the same coordinate system to create a point cloud.

Once the point cloud is generated, one or more machine learningalgorithms may be used to cluster points into objects, and ultimatelycharacterize the respective material(s) of each object (e.g., where aplurality of objects is detected). Points may be clustered based on, forexample, one or more values of the measured intensities, also, in someexamples, based on proximity of similar points.

Once a cluster is determined using intensity values, a machine learningalgorithm may be used to correlate the measured value to a database ofknown materials to classify the material of that cluster of points. Thisprocess may be repeated for all clusters in the system. An understandingof surrounding materials enables the system (e.g., as implemented in anautomobile, robot, drone, etc.) to make faster, more educated decisionsabout what the objects themselves might be. From there, factors such asrisk involved can be assessed and decisions can be subsequently made(e.g., in the case of the system detecting black ice ahead of avehicle). As the process continues over time, more information can beextracted from changes perceived and an even better understanding of thesurroundings developed.

The MST classification technology is also applicable to the detection ofan object whose surface is modified to enhance detection, for example,that is painted or textured with a macroscale, microscale, nanoscale, ormolecular pattern to produce the reflected beams with the specificoptical response adapted to the fast MST classification by LIDARs.Examples of such surface treatment include paints containing additivesthat produce reflected, scattered or otherwise emitted light withspecific linear, circular, or elliptical polarization. In one instance,metal nano/micro/macro wires or axial carbon nanomaterials are added tothe base paint. An alignment pattern can be random, linear, spiral,herring-bone or any other pattern that produces the specificpolarization signature enabling fast identification of a specificobject. By way of non-limiting example, this may be used for creatingmarkers on roads, road signs, barriers, pylons, guard rails, vehicles,bicycles, clothing, and other objects.

Another implementation of surface treatment facilitating MSTclassification may include the addition of chiral inorganicnanoparticles to base paint used to coat such objects described above,such as road markers, vehicles, bicycles, clothing, etc. The chiralnanoparticles may display a specific and very strong circularpolarization response to the beams used by the LIDARs. They can be mixedin the paint with a specific ratio to create polarization signatures(e.g., “bar-codes”) for specific objects.

Another example of polarization tagging of an object may include usingsurface texturing that creates a particular polarization response. Oneexample of such texturing may include creating nanoscale patterns ofmetal, semiconductor, insulating or ceramic nanoparticles with specificgeometrical characteristics resulting in a defined polarization responseto the laser in LIDARs. Two examples of such patterns include (a) linearnanoscale or microscale surface features that result in a linearpolarization of the reflected, scattered, or emitted light from anobject and (b) out-of-plane protruding chiral patterns on the metalsurfaces resulting in a specific chirality and therefore circularpolarization of the reflected, scattered, or emitted light from anobject.

According to some examples, the foregoing system and method may beemployed to accurately recognize materials for use in autonomousvehicles, machine learning, medical applications, and advanced robotics.

Existing, conventional LIDAR systems primarily work via measurement ofthe distance between an object and the laser source, typically usingeither time-of-flight data or phase shifts. In such cases, the objectsare classified based on geometries and patterns in the arrangement ofpoints in the cloud. Some more advanced LIDAR point cloud classificationmethods make use of an additional parameter: overall intensity.

Based on how strong the signal of the returning light pulse is, a systemcan effectively detect differences in color. This additional piece ofdata makes it easier to recognize object boundaries within point clouds,decreasing the amount of processing required to classify all points.However, applications like autonomous vehicles may require a higherdegree of certainty, which overall intensity cannot achieve.Furthermore, the detection of objects at long distances may be achievedwith a single point detection taking advantage of MST classification,rather than multiple point detection and processing of the type employedin conventional LIDAR systems.

Accordingly, the method described herein changes the approach machinevision currently takes towards object recognition. Instead of solelyrelying on geometry, movement, and color to determine the identity of anobject, the system described herein takes into account yet anotherparameter: polarization. Upon reflecting off of a material interface,light experiences some change in polarization. This polarization changeis quantified by measuring the intensities of light after having passedthrough both co-polarized and cross-polarized filters. This additionaldata may be paired with machine learning approaches to significantlyimprove clustering, and by extension, object recognition capabilities.Traditional object recognition methods are quite computationallyexpensive. The approach described herein may significantly reduce theprocessing power required by LIDAR by using a material-based approachrather than the current, geometry-based approach.

In addition to traditional distance measurements, the polarization datacollected by the instant system allows machine learning algorithms todetermine the material(s) from which an object is composed. CurrentLIDAR systems lack awareness or information about the materials in asurrounding environment. When achieved, such information providescontext for greater situational understanding and smarter decisions. Inthe case of an autonomous vehicle, this enhanced understanding of theenvironment may lead to improved safety of the passengers becauseaccurate, timely detection of potential hazards produce improveddecision-making capabilities.

Turning now to FIGS. 2a-2b , scanning electron microscope (SEM) imagesof nano-kirigami sheets are shown that may be used to form thenano-kirigami nanocomposite optic components incorporated into anM-LIDAR system. The optically active kirigami sheets, such as thoseshown in FIGS. 2a-2b , may be manufactured from ultra-strong nanoscalecomposites with cut patterns of 0.5-5 μm in length, according to someexamples of the present disclosure. In certain aspects, compositematerials (including highly conductive composite materials) can bemodified by using a concept from the ancient Japanese art of papercutting known as “kirigami.” The present disclosure thus provides akirigami approach to engineer elasticity by using a plurality of cuts ornotches that create a network on a planar polymeric material, such as acomposite or nanocomposite material. Such cuts (extending from one sideto the other of the material, for example, in a polymeric or compositematerial) can be made by top-down patterning techniques, such asphotolithography, to uniformly distribute stresses and suppressuncontrolled high-stress singularities within the polymeric ornanocomposite material. This approach can prevent unpredictable localfailure and increases the ultimate strain of rigid sheets from 4% to370%, by way of non-limiting example.

By using microscale kirigami patterning, a stiff nanocomposite sheet canacquire high extensibility. Moreover, kirigami cut-patterned compositesheets maintain their electrical conductance over the entire strainregime, in marked contrast to most stretchable conductive materials. Thekirigami structure may comprise a composite, such as a nanocomposite. Incertain aspects, the kirigami structure may be a multilayered structurehaving at least two layers, where at least one layer is a polymericmaterial. The polymeric material may be a composite or nanocompositematerial. The composite material comprises a matrix material, such as apolymer, a polyelectrolyte, or other matrix (e.g., cellulose paper), andat least one reinforcement material distributed therein. In certainaspects, nanocomposite materials are particularly suitable for use in akirigami structure, which is a composite material comprising areinforcement nanomaterial, such as nanoparticles. The composite may bein the form of a sheet or film in certain variations.

A “nanoparticle” is a solid or semi-solid material that can have avariety of shapes or morphologies, however, which are generallyunderstood by those of skill in the art to mean that the particle has atleast one spatial dimension that is less than or equal to about 10 μm(10,000 nm). In certain aspects, a nanoparticle has a relatively lowaspect ratio (AR) (defined as a length of the longest axis divided bydiameter of the component) of less than or equal to about 100,optionally less than or equal to about 50, optionally less than or equalto about 25, optionally less than or equal to about 20, optionally lessthan or equal to about 15, optionally less than or equal to about 10,optionally less than or equal to about 5, and in certain variations,equal to about 1. In other aspects, a nanoparticle that has a tube orfiber shape has a relatively high aspect ratio (AR) of greater than orequal to about 100, optionally greater than or equal to about 1,000, andin certain variations, optionally greater than or equal to about 10,000.

In certain variations, a nanoparticle's longest dimension is less thanor equal to about 100 nm. In certain embodiments, the nanoparticlesselected for inclusion in the nanocomposite are electrically conductivenanoparticles that create an electrically conductive nanocompositematerial. The nanoparticles may be substantially round-shapednanoparticles, that have low aspect ratios as defined above, and thathave a morphology or shape including spherical, spheroidal,hemispherical, disk, globular, annular, toroidal, cylindrical, discoid,domical, egg-shaped, elliptical, orbed, oval, and the like. In certainpreferred variations, the morphology of the nanoparticle has a sphericalshape. Alternatively, the nanoparticle may have an alternative shape,such as a filament, fiber, rod, a nanotube, a nanostar, or a nanoshell.The nanocomposite may also include combinations of any suchnanoparticles.

Furthermore, in certain aspects, a particularly suitable nanoparticlefor use in accordance with the present teachings has a particle size (anaverage diameter for the plurality of nanoparticles present) of greaterthan or equal to about 10 nm to less than or equal to about 100 nm. Theconductive nanoparticles may be formed of a variety of conductivematerials including metallic, semiconducting, ceramic, and/or polymericnanoscale particles having plurality of shapes. The nanoparticles mayhave magnetic or paramagnetic properties. The nanoparticles may compriseconductive materials, such as carbon, graphene/graphite, graphene oxide,gold, silver, copper, aluminum, nickel, iron, platinum, silicon,cadmium, mercury, lead, molybdenum, iron, and alloys or compoundsthereof. Thus, suitable nanoparticles can be exemplified by, but are notlimited to, nanoparticles of graphene oxide, graphene, gold, silver,copper, nickel, iron, carbon, platinum, silicon, seedling metals, CdTe,CdSe, CdS, HgTe, HgSe, HgS, PbTe, PbSe, PbS, MoS₂, FeS₂, FeS, FeSe,WO_(3-x), and other similar materials known to those of skill in theart. Graphene oxide is a particularly suitable conductive material foruse as reinforcement in the composite. In certain variations, thenanoparticles can comprise carbon nanotubes, such as single wallednanotubes (SWNTs) or multi-walled nanotubes (MWNTs), for example. SWNTsare formed from a single sheet of graphite or graphene, while MWNTsinclude multiple cylinders arranged in a concentric fashion. The typicaldiameters of SWNT can range from about 0.8 nm to about 2 nm, while MWNTcan have diameters in excess of 100 nm.

In certain variations, the nanocomposite may comprise a total amount ofa plurality of nanoparticles of greater than or equal to about 1% byweight to less than or equal to about 97% by weight, optionally greaterthan or equal to about 3% by weight to less than or equal to about 95%by weight, optionally greater than or equal to about 5% by weight toless than or equal to about 75% by weight, optionally greater than orequal to about 7% by weight to less than or equal to about 60% byweight, optionally greater than or equal to about 10% by weight to lessthan or equal to about 50% by weight of a total amount of nanoparticlesin the nanocomposite. Of course, appropriate amounts of nanoparticles ina composite material depend upon material properties, percolationthresholds, and other parameters for a particular type of nanoparticlein a specific matrix material.

In certain variations, the nanocomposite may comprise a total amount ofa polymeric matrix material of greater than or equal to about 1% byweight to less than or equal to about 97% by weight, optionally greaterthan or equal to about 10% by weight to less than or equal to about 95%by weight, optionally greater than or equal to about 15% by weight toless than or equal to about 90% by weight, optionally greater than orequal to about 25% by weight to less than or equal to about 85% byweight, optionally greater than or equal to about 35% by weight to lessthan or equal to about 75% by weight, optionally greater than or equalto about 40% by weight to less than or equal to about 70% by weight of atotal amount of matrix material in the nanocomposite.

In certain variations, the nanocomposite material comprises a pluralityof electrically conductive nanoparticles and has an electricalconductivity of greater than or equal to about 1.5×10³ S/cm. In certainother aspects, the nanocomposite material may comprise a plurality ofelectrically conductive nanoparticles as a reinforcement nanomaterialand thus may have an electrical resistivity of less than or equal toabout 1×10⁻⁴ Ohm·m. In certain other variations, an impedance (Z) of theelectrically conductive nanocomposite comprising a plurality ofnanoparticles may be less than or equal to about 1×10⁴ Ohms (e.g.,measured using an AC sinusoidal signal of 25 mV in amplitude withimpedance values measured at a frequency of 1 kHz).

The polymeric or nanocomposite material may be in a planar form, such asa sheet, in an initial state (prior to being cut), but may be folded orshaped into a three-dimensional structure and thus used as a structuralcomponent after the cutting process. By way of example, a structure 220including a portion of an exemplary nanocomposite material sheet 230having a surface with tessellated cut pattern is shown in FIG. 10. Sheet230 includes a first row 232 of first discontinuous cuts 242 (thatextend through the sheet 230 to create an opening) in a pattern thatdefines a first uncut region 252 between the discontinuous cuts 242. Adiscontinuous cut is a partial or discrete cut formed in the sheet thatleaves the entire sheet intact in its original dimensions, rather thanbeing divided into separate smaller sheets or portions. If multiplediscontinuous cuts 242 are present, at least some of them arenoncontiguous and unconnected with one another so that at least oneuncut region remains on the sheet as a bridge between the discontinuoussheets. While many cut patterns are possible, a simple kirigami patternof straight lines in a centered rectangular arrangement as shown in FIG.10 is used herein as an exemplary pattern. The first uncut region 252has a length “x.” Each discontinuous cut 242 has a length “L.”

In certain aspects, the length of each discontinuous cut (e.g.,discontinuous cut 242) may be on the micro- meso-, nano- and/ormacroscales. Macroscale is typically considered to have a dimension ofgreater than or equal to about 500 μm (0.5 mm), while mesoscale isgreater than or equal to about 1 μm (1,000 nm) to less than or equal toabout 500 μm (0.5 mm). Microscale is typically considered to be lessthan or equal to about 100 μm (0.5 mm), while nanoscale is typicallyless than or equal to about 1 μm (1,000 nm). Thus, conventionalmesoscale, microscale, and nanoscale dimensions may be considered tooverlap. In certain aspects, the length of each discontinuous cut may beon a microscale, for example, a length that is less than about 100 μm(i.e., 100,000 nm), optionally less than about 50 μm (i.e., 50,000 nm),optionally less than about 10 μm (i.e., 10,000 nm), optionally less thanor equal to about 5 μm (i.e., 5,000 nm), and in certain aspects lessthan or equal to about 1 μm (i.e., 1,000 nm). In certain aspects, thediscontinuous cuts 42 may have a length that is less than about 50 μm(i.e., 50,000 nm), optionally less than about 10 μm (i.e., 10,000 nm),and optionally less than about 1 μm (i.e., less than about 1,000 nm).

In certain other variations, these dimensions can be reduced by at least100 times to a nanoscale, for example a cut having a length of less thanor equal to about 1 μm (1,000 nm), optionally less than or equal toabout 500 nm, and in certain variations, optionally less than or equalto about 100 nm.

It should be noted that “x” and “L” may vary within rows depending onthe pattern formed, although in preferred aspects, these dimensionsremain constant.

A second row 234 of second discontinuous cuts 244 is also patterned onthe sheet 230. The second discontinuous cuts 244 define a second uncutregion 254 therebetween. A third row 236 of third discontinuous cuts 246is also patterned on the sheet 230. The third discontinuous cuts 246define a third uncut region 256 therebetween. It should be noted thatthe first row 232, second row 234, and third row 236 are used forexemplary and nominative purposes, but as can be seen, the tessellatedpattern on the surface of sheet 230 has in excess of three distinctrows. The first row 232 is spaced apart from the second row 234, asshown by the designation “y.” The second row 234 is likewise spacedapart from the third row 236. It should be noted that “y” may varybetween rows, although in certain aspects, it remains constant betweenrows. Such spacing between rows may likewise be on a micro- meso-, nano-and/or macroscale, as described above.

Notably, the first discontinuous cuts 242 in the first row 232 areoffset in a lateral direction (along the dimension/axis shown as “x”)from the second discontinuous cuts 244 in the second row 234, thusforming a tessellated pattern. Likewise, the second discontinuous cuts244 in the second row 234 are offset in a lateral direction from thethird discontinuous cuts 246 in the third row 236. Thus, the first uncutregion 252, second uncut region 254, and third uncut region 256 in eachrespective row cooperates to form a structural bridge 260 that extendsfrom the first row 232, across second row 234, and to third row 236.

In this regard, the sheet 230 having the patterned tessellated surfacewith the plurality of discontinuous cuts (e.g., 242, 244, and 246) canbe stretched in at least one direction (e.g., along the dimension/axisshown as “y” or “x”). The sheet 230 formed of a nanocomposite thusexhibits certain advantageous properties, including enhanced strain.

In various aspects, an optic device incorporating a stretchablemultilayered polymeric or composite material formed by a kirigamiprocess is contemplated. By “stretchable” it is meant that materials,structures, components, and devices are capable of withstanding strain,without fracturing or other mechanical failure. Stretchable materialsare extensible and thus are capable of stretching and/or compression, atleast to some degree, without damage, mechanical failure or significantdegradation in performance.

“Young's modulus” is a mechanical property referring to a ratio ofstress to strain for a given material. Young's modulus may be providedby the expression:

$E = {\frac{({stress})}{({strain})} = {\frac{\sigma}{\epsilon} = {\frac{L_{o}}{\Delta L} \times \frac{F}{A}}}}$where engineering stress is σ, tensile strain is ϵ, E is the Young'smodulus, L₀ is an equilibrium length, ΔL is a length change under theapplied stress, F is the force applied and A is the area over which theforce is applied.

In certain aspects, stretchable composite materials, structures,components, and devices may undergo a maximum tensile strain of at leastabout 50% without fracturing; optionally greater than or equal to about75% without fracturing, optionally greater than or equal to about 100%without fracturing, optionally greater than or equal to about 150%without fracturing, optionally greater than or equal to about 200%without fracturing, optionally greater than or equal to about 250%without fracturing, optionally greater than or equal to about 300%without fracturing, optionally greater than or equal to about 350%without fracturing, and in certain embodiments, greater than or equal toabout 370% without fracturing.

Stretchable materials may also be flexible, in addition to beingstretchable, and thus are capable of significant elongation, flexing,bending or other deformation along one or more axes. The term “flexible”can refer to the ability of a material, structure, or component to bedeformed (for example, into a curved shape) without undergoing apermanent transformation that introduces significant strain, such asstrain indicating a failure point of a material, structure, orcomponent.

Thus, the present disclosure provides in certain aspects, a stretchablepolymeric material. In further aspects, the present disclosure providesa stretchable composite material that comprises a polymer and aplurality of nanoparticles or other reinforcement materials. The polymermay be an elastomeric or thermoplastic polymer. One suitable polymerincludes polyvinyl alcohol (PVA), by way of non-limiting example.

For example, for certain materials, creating the surface havingpatterned kirigami cuts in accordance with certain aspects of thepresent disclosure can increase ultimate strain of initially rigidsheets to greater than or equal to about 100% from an initial ultimatestrain prior to any cutting, optionally greater than or equal to about500%, optionally greater than or equal to about 1,000%, and in certainvariations, optionally greater than or equal to about 9,000%.

Notably, a wide range of maximum attainable strains or expansion levelscan be achieved based on the geometry of the cut pattern used. Theultimate strain is thus determined by the geometry. The ultimate strain(% strain) is a ratio between a final achievable length, while beingstretched to a point before the structure breaks, over the original orinitial length (L_(i)):

$\%\mspace{14mu}{strain}{= {\frac{\Delta L}{L_{i}} = \frac{L_{c} - x - {2y}}{2y}}}$where L_(c) is a length of the cut, x is spacing between discontinuouscuts, and y is distance between discrete rows of discontinuous cuts.Thus, in certain variations, the polymeric materials, such asnanocomposites, having a surface with patterned cuts in accordance withcertain aspects of the present disclosure can increase ultimate strainto greater than or equal to about 100%, optionally greater than or equalto about 150%, optionally greater than or equal to about 200%,optionally greater than or equal to about 250%, optionally greater thanor equal to about 300%, optionally greater than or equal to about 350%,and in certain variations, optionally greater than or equal to about370%. Additional discussion on kirigami composite materials and methodsof making them are described in U.S. Publication No. 2016/0299270 filedas U.S. application Ser. No. 15/092,885 filed on Apr. 7, 2016 to Kotovet al. entitled “Kirigami Patterned Polymeric Materials and TunableOptic Devices Made Therefrom,” the relevant portions of which areincorporated herein by reference.

In certain aspects, the kirigami nanocomposites can form tunable opticalgrating structures that can maintain stable periodicity over macroscopiclength scale even under 100% stretching. The lateral spacing indiffraction patterns shows negative correlation with the amount ofstretch, which is consistent with the reciprocal relationship betweenthe dimensions in diffraction pattern and the spacing of thecorresponding grating. The longitudinal spacing in the diffractionpatterns exhibits less dependency on the amount of stretch, owing to therelatively small changes in longitudinal periodicity with lateralstretch. The diffraction patterns also show significant dependence onthe wavelength of the incoming laser. The polymeric stretchable tunableoptic grating structures present elastic behavior with the stretch andspontaneously recovers to the relaxed (i.e., un-stretched) geometry asthe stretch is removed under cyclic mechanical actuation. The diffractedbeams form clear patterns that change consistently with the deformationof the polymeric stretchable tunable optic grating structures. Thisbehavior indicates excellent capability for dynamic,wavelength-dependent beam steering.

Three-dimensional (3D) kirigami nanocomposites thus provide a newdimension to traditional reflective and refractive optics due to theout-of-plane surface features, as illustrated in FIGS. 2a-2b . Forexample, the reconfigurable fins and slits formed by the cutsillustrated in the nano-kirigami sheets shown in FIGS. 2a-2b allow forefficient modulation of light by reversible expansion (or strain levels)of the kirigami cut sheets. Consequently, nano-kirigami sheets such asthose shown in FIGS. 2a-2b may be incorporated into one or more opticcomponents of the M-LIDAR system described here. More specifically,these light, thin and inexpensive optical components may be used, forexample, for the red and infrared portions of the light spectrum toachieve beam steering and/or polarization modulation. According to someimplementations, kirigami nanocomposites of the type shown in FIGS.2a-2b may be utilized to form the beam steer 106, s-polarization linearpolarizer 114, and/or p-polarization linear polarizer 116 of the systemillustrated in FIG. 1.

In certain variations, kirigami nanocomposites can form kirigami opticalmodules manufactured from ultrastrong layer-by-layer (LbL) assemblednanocomposites. These nanocomposite materials having high strength, forexample, about 650 MPa and an elastic modulus (E) of about 350 GPa, forexample, providing exceptional mechanical properties, environmentalrobustness, along with a wide temperature range of operations (e.g.,from −40° to +40° C.), and proven scalability. High elasticity of LbLcomposites makes them reconfigurable and their high temperatureresilience enables integration with different types of actuators andCMOS compatibility. In certain aspects, the nanocomposite material maybe coated with plasmonic films such as titanium nitride, gold, and thelike to enhance interaction with target wavelengths of photons, forexample, 1550 nm photons where the laser source has a wavelength of 1550nm.

In certain other variations, the kirigami nanocomposite sheets caninclude magnetic materials distributed therein or coated thereon. Forexample, a layer of nickel may be deposited on an ultra-strongcomposite. The layer of nickel can serve as a magnetic and reflectivelayer, thus providing a magentoactive kirigami element. The kirigamiunits thus can be directly integrated with LIDAR components and serve asbeam steerers (for example, using first and second order diffractionbeams) or as polarizers (for example, using the first order diffractionbeams).

Referring now to FIGS. 3a-3c , images depicting laser diffractionpatterns from nano-kirigami-based graphene composites are shown. Forreference, the scale bars shown in the upper right hand corners of FIGS.3a-3c represent 25 mm. FIG. 3a depicts the laser diffraction pattern fornano-kirigami-based graphene composites for 0% strain (relaxed state).FIG. 3b depicts the laser diffraction pattern for fromnano-kirigami-based graphene composites for 50% strain. Finally, FIG. 3cdepicts the laser diffraction pattern for from nano-kirigami-basedgraphene composites for 100% strain.

Polarization modulation of LIDAR beams and polarization analysis ofreturned photons will enable the acquisition of information about theobject material that is currently lacking in, for example, car safetyand robot vision devices. Machine Learning (ML) algorithms may betrained to recognize different materials and MST classification based ontheir unique polarization signatures may be achieved. The MSTclassification of objects by material may, among other advantages,accelerate object recognition and improve the accuracy of machineperception of surroundings.

Before turning to the specifics of FIGS. 4a-4d , it bears noting thatsystem 100 of FIG. 1 and corresponding methods of material detection andobject classification may be carried out, according to some examples ofthe present disclosure, utilizing non-nano-kirigami optical elements.Indeed, such non-nano-kirigami optical element-based M-LIDAR systems maybe preferred for certain applications (e.g., where size and weight arenot major concerns). Accordingly, implementations of the presentlydisclosed M-LIDAR system in which nano-kirigami optical elements are notutilized, other traditional optical components such as (i) IRpolarizers; (ii) beam splitters; (iii) lenses made from CdS, ZnS,silicon; and/or (iv) similarly suitable optical elements may be equallyemployed without deviating from the teachings herein. However,nano-kirigami optical elements are generally favored for M-LIDAR systemsthat benefit from being light and small.

With that as a backdrop, FIGS. 4a-4d illustrate a step-by-steplithographic-type process for manufacturing a nano-kirigami-basedoptical element, such as a beam splitter or linear polarizer. Accordingto one example, the process for manufacturing the nano-kirigami-basedoptical element set forth in FIGS. 4a-4d may include using a vacuumassisted filtration (VAF), whereby nanocomposite material may bedeposited as a layer on a stiff (e.g., plastic) substrate suitable forlithographic patterning. As noted above, U.S. Publication No.2016/0299270 describes methods of making such nanocomposite materials,including by vacuum assisted filtration (VAF) and layer-by-layer (LBL)deposition process techniques. Nanocomposites manufactured according tothis process are known to display high toughness and strong lightabsorption.

FIG. 4a . is a simplified illustration of the first step of the process400 whereby a nanocomposite layer 404 a is deposited on a substrate 402via VAF, layer-by-layer deposition (LBL), or any other suitabledeposition method known in the art. FIG. 4b illustrates the second stepin the process 400 after the nanocomposite 404 a of FIG. 4 has beenpatterned to produce a patterned kirigami nanocomposite 404 b throughselect regions of the nanocomposite layer 404 a, for example, via aphotolithographic cutting process, atop the substrate 402. FIG. 4cillustrates the third step in the process 400 whereby the cut orpatterned kirigami nanocomposite 404 b is released (e.g., lifted) fromthe substrate 402. Finally, FIG. 4d illustrates the final step of theprocess 400 whereby at least a portion of the patterned kirigaminanocomposite 408 has been incorporated into a subassembly configuredfor, among other things, beam steering and/or modulation.

The subassembly shown in FIG. 4d includes the patterned kirigaminanocomposite portion 408, a microfabricated silicon layer 406 housing,and one or more bent beam actuators 410. Dual sided arrows 412illustrate the potential directions of the actuator 410 motions. Asdiscussed in additional detail below, the bent beam actuators 410 may beconfigured to exert reversible strain on the kirigami nanocompositeportion 408 so as to, for example, adjust the size and/or orientation ofvarious slits and/or fins making up the pattern of the kirigaminanocomposite portion 408. Thus, the kirigami nanocomposite portion 408may thus be reversibly stretched at strain levels ranging from 0% to100%.

A more detailed discussion of the patterning aspect of the process 400shown in FIGS. 4a-4d follows. The manufacturing of the kirigamitransmissive optical modules may follow the step-by-step diagram shownin FIGS. 4a-4d . The modulation of LIDAR laser beams in visible and IRranges may require feature sizes at, for example, 3 μm, created over0.1-1 cm widths. The feasibility of such patterns has already beendemonstrated. The 2D geometry of the patterns may be selected based oncomputer simulations of their 2D to 3D reconfiguration when stretched orstrained. The 3D geometry may be modeled for optical properties, forinstance, polarization modulation in the desirable wavelength range.Photolithography may be a primary patterning tool, enabled by thechemistry of VAF composites described above. The patterning protocol maybe substantially similar to that currently being used for large scalemicrofabrication. For example, VAF composites on glass substrates may becoated by standard SU8 photoresist following photo patterning usingcommercial conventional mask aligner. Examples of kirigami patternsprepared are shown in FIGS. 5a-5c , discussed in greater detail below.

Kirigami optical elements may be manufactured by integrating kirigaminanocomposite sheets with commercial microelectromechanical actuators asshow, for example, in FIG. 4d . The microelectromechanical systems(MEMS) kirigami units may be directly integrated with LIDAR componentsand serve as beam steerers (using, for example, first and second orderdiffraction beams) and/or polarizers (using, for example, the firstorder diffraction beams). Considering the nearly endless number ofkirigami patterns and wide variety of 2D to 3D reconfigurations,kirigami optical elements with both beam steering and polarizationcapabilities, as well as other optical functions, are contemplatedwithin the teachings herein.

With brief reference to FIGS. 5a-5c , various images of example kirigamioptical elements are shown. For example, FIG. 5a is an image of akirigami optical element, such as the kirigami optical elementsdescribed herein, fabricated on a wafer in line with the process 400described above with regard to FIGS. 4a-4d . FIG. 5b is a SEM image ofthe kirigami optical element of FIG. 5a under 0% strain. Finally, FIG.5c is a SEM image of the kirigami optical element of FIG. 5a under 100%strain. The scale bars depicted in the upper right hand corners of FIGS.5b-5c are 50 μm.

Photolithographic techniques can be used to manufacture kirigamitransmissive or reflective optical modules/elements. By way of example,modulation of LIDAR laser beams having a wavelength of about 1550 nm mayhave feature sizes from greater than or equal to about 1 μm to less thanor equal to about 2 μm, created over widths ranging from greater than orequal to about 0.1 cm to less than or equal to about 1 cm exemplified bythe current patterns in FIGS. 5a-5c . The two dimensional (2D) geometryof the patterns can be selected based on computer simulations of their2D to three dimensional (3D) reconfiguration when stretched. The 3Dgeometry can be modeled for optical properties, for instance,polarization modulation in the desirable wavelength range.

Photolithography is a primary patterning technique that can be used incombination with LbL composites to form kirigami optical elements. Inone example, the patterning protocol can include providing an LbLcomposite on a glass substrate that is coated by a standard SU-8photoresist following photo patterning using a commercial mask aligner(UM Lurie Nanofabrication Facility, LNF). Such a process can formkirigami elements like those shown in FIGS. 5a -5 c.

Another representative simplified compact M-LIDAR system 300 for use ina vehicle, such as an autonomous vehicle, is provided in FIG. 11. To theextent that the components in the M-LIDAR system 300 are similar tothose in the M-LIDAR system 100 of FIG. 1, for brevity, their functionwill not be repeated herein. The M-LIDAR system 300 may include a laser310, a beam steerer 312, one or more polarizers (not shown, but similarto the first polarizer 114 and second polarizer 116 described in thecontext of FIG. 1), and a processor (not shown, but similar to processor126 that shown in FIG. 1). In the M-LIDAR system 300, a pulse generator312 is connected to laser 310 and generates a polarized or unpolarizedfirst light pulse 314 and a polarized or unpolarized second light pulse316. The pulse generator 312 is connected to an oscilloscope 324. Thefirst light pulse 314 and second light pulse 316 generated by laser 310are directed towards a beam steerer 318, which may in certain aspects,be a kirigami-based beam steerer like those discussed previously above.The beam steerer 318 is connected to and controlled by aservo-motor/Arduino 352. The servo-motor/Arduino 352 is connected to acontroller 350 that may be a MATLAB™ control, by way of non-limitingexample. As noted previously above, the beam steerer 318 may polarize,modify, split, and/or modulate one or both of the first light pulse 314and second light pulse 316 by way of non-limiting example, as discussedpreviously above. The first light pulse 314 and second light pulse 316are then directed towards an object 340 to be detected.

The first light pulse 314 and second light pulse 316 may be diffusivelyreflected off the object 110. One or more pulses of light collectivelyform a first reflected beam 342 and a second reflected beam 344 thatconstitutes a reflected version of the first light pulse 314 and secondlight pulse 316. According to some examples, the first reflected beam342 and the second reflected beam 344 may have a different polarizationthan the first light pulse 314 and second light pulse 316 (i.e., priorto reflection off of the object 340). After reflecting from the object340, the first reflected beam 342 and second reflected beam 344 may bedirected towards an off-axis parabolic reflector/mirror 330 thatredirects the first reflected beam 342 and second reflected beam 344towards a beam splitter 360.

The first reflected beam 342 is thus split and directed to both a firstdetector 362 and a second detector 364. The first detector 362 and thesecond detector 364 may be connected to the oscilloscope 324. The firstdetector 362 may be an s-polarization detector configured to detect anintensity of one or more reflected s-polarization light pulses formingthe first reflected light beam 342. Likewise, the second detector 364may be a p-polarization detector configured to detect an intensity ofone or more reflected p-polarization light pulses forming the firstreflected light beam 342. After passing through beam splitter 360, thesecond reflected light beam 344 is directed to both the first detector362 and the second detector 364, where an intensity of thes-polarization light pulses and/or p-polarization light pulses can bedetected from the second reflected light beam 344. The first detector362 and the second detector 364 may be connected to a processor (notshown), which further analyzes information received therefrom asdescribed previously above. The M-LIDAR system 300 is compact and mayhave dimensions of about 7 inches by 12 inches, by way of non-limitingexample, making it particularly suitable to mount in a vehicle.

MST classification, as introduced above, may be realized according toexamples of the present disclosure through the use of light source-basedMST classification with light polarization classifiers added to pointclouds. In one example, for each 3D range measurement of a point cloud,linear/circular polarization of returned photons may be acquired. Inaddition, local curvature and local scattering conditions may be madedirectly based on the polarization state of the returned photons,although the relationship between surface properties and polarizationstate may, in some instances, be noisy due to surface roughness.

Referring now to FIG. 6, MST polarization analysis of reflected laserlight was performed using AI data processing with a neural networkalgorithm to produce the confusion matrix of FIG. 6. More specifically,the confusion matrix was produced based on analysis of s and p-polarizedlight beams (such as the s and p-polarized light beams 118, 120 shown inFIG. 1). Along the x-axis, predicted types of materials for a testobject subjected to the M-LIDAR system and processing methods describedherein are identified. Along the y axis, the true types of materials forthe test object are identified. The accuracy of various predictions ofthe AI algorithm for the various material types are reflected at theintersections of the predicted material types and true material types.As shown, the materials detection functionality of the M-LIDAR systemmay be accomplished with a high degree of accuracy (including at orabove 99% in some instances) using these polarized light beams.

Referring now to FIG. 7, a confusion matrix for the detection ofsimulated black ice compared to other materials is shown. Again, thematerials detection functionality of the M-LIDAR system may beaccomplished with a high degree of accuracy (including at 100% in someinstances).

FIG. 8 illustrates one example of an M-LIDAR device 800 for use in, forexample, black ice detection (e.g., when installed in a vehicle or thelike). While the present example focuses on a black-ice detectionapplication, those having ordinary skill will recognize that the device800 is not limited to black ice detection, and may be suitably employedfor a wide range of material detection and object classificationapplications, including on autonomous vehicles. The device 800 includesa housing 802, an emitter 804 (i.e., an emitter for emitting lightpulses making up a laser light beam), a first detection 806 a, and asecond detector 806 b. According to one example, one or more of thedetectors 806 a, 806 b include orthogonal polarization analyzers.Furthermore, according to one example, one or more of the emitter 804,detector 806 a, and/or detector 806 b may be made with kirigami opticalelements. Although the primary example of the device is use within anautomobile, the device could also be used, for example, within anaircraft, such as a drone or the like.

Referring now to FIG. 9, a flowchart illustrating a method 900 ofperforming object classification using an M-LIDAR system is provided.The method 900 begins at 902 where an unpolarized light pulse isgenerated. At 904, the unpolarized light pulse is linearly polarized toproduce a linearly polarized light pulse. The linearly polarized lightpulse may be emitted towards an object and reflect back off of theobject to produce a reflected linearly polarized light pulse. At 906,the reflected linearly polarized light pulse may be linearly polarizedfor s-polarization to produce a reflected s-polarization light pulse.

At 908, the reflected linearly polarized light pulse may be linearlypolarized for p-polarization to produce a reflected p-polarization lightpulse. At 910, an intensity of the reflected s-polarization light pulsemay be detected. At 912, an intensity of the reflected p-polarizationlight pulse may be detected. At 914, at least one material of the objectmay be detected based on the intensity of the reflected s-polarizationlight pulse and the intensity of the reflected p-polarization lightpulse. Finally, at 916, the object may be classified based on thedetected at least one material. Following 916, the method 900 concludes.

Finally, according to some examples, kirigami patterns may be used asMST tags for the polarization-based detection of objects. Mass-producedkirigami components can also be added to paints to impart a specificpolarization response in road signs, clothing, markers, vehicles,household items, or any other suitable objects.

In certain variations, LIDAR systems of the present disclosure canprovide modulation of transmitted and reflected beams. Kirigami-basedoptical elements can be added to an emitter side of the LIDAR to serveas beam steerers, which can thus replace conventional bulky rotationalor liquid crystal phase array beam steerers. Magnetic actuation modulescan be integrated with a 1550 nm laser source. To reduce the bulk of thebeam steerer, fiber optics can be coupled directly with the module.

In certain variations, LIDAR systems provided by the present disclosuremay provide enhanced detection in precipitation and/or humid atmosphericconditions. For example, the LIDAR systems contemplated by the presentdisclosure may be particularly suitable for use in low visibilityconditions by employing a laser with a wavelength of about 1550 nm, byway of non-limiting example, which provides enhanced detection andperformance during poor weather conditions, including low visibilityconditions that accompany fog, rain, and snow. Such LIDAR systems canenable long-range warnings, for example, up to 200 meters, which isespecially useful for highway driving conditions. Conventional LIDARsuse laser with wavelengths of about 900 nm, which is convenient forsilicon-based detectors. However, these conventional laser beamsexperience relatively strong scattering in humid atmospheric conditions.LIDARs operating with 1550 nm can utilize high transparency of humidair, which is advantageous for all different levels of autonomy fromproximity warnings to assisted driving and full autonomous ridemodality. However, such LIDARs can be bulky and expensive due to highweight and cost of near-infra-red optics. In accordance with certainaspects of the present disclosure, kirigami-based optic elements canresolve this issue by taking advantage of the space-charge andsubwavelength effects possible for the patterned kirigami sheets, seefor example, FIGS. 2a-2b . As shown in FIGS. 3a-3b , such kirigamisheets can effectively modulate and beam steer near-infrared lightlasers using the reconfigurable out-of-plane patterns of the kirigamisheets. A 1550 nm beam steering device incorporating such kirigami-basedoptical elements can be used as thin, light, and inexpensive solid-stateLIDAR. Furthermore, the versatility of kirigami technology allows one topotentially adapt patterns for specific applications, for example,customizing the LIDAR system to specific vehicles and/or to adapt it tosurfaces of different curvature of automotive parts.

In certain aspects, the present disclosure can provide LIDAR systemswith relatively fast detection, by using two-stage object proposal anddetection methods without sacrificing accuracy for latency. For example,improved model accuracy and generalizability for classification modelscan include enhancing static object classifiers by adding a materialdimension to data. Objects with material fingerprints that containplastic, wood and brick are very unlikely to move, while those withmetal or fabric fingerprints are more likely be pedestrians andvehicles. Moreover, as the material dimension is more robust to scenariovariations, these models generalize better to rare and complicatedcases, such as construction sites and streets with complex festivaldecorations. Thus, material fingerprints greatly enhance model accuracyfor point cloud association models with impact on tracking andautonomous vehicle maps. For example, the material dimension of thepoint clouds can make the detection and classification much morereliable, as pedestrians walking with bicycles can be picked up as pointclouds, with metal materials on the lower side with some fabric or skinfeatures from the pedestrian. It is then much easier for theself-driving systems to discern it from a pure pedestrian. Also, thematerial fingerprints of the object make it easier for the system toassociate the point clouds with the correct object classification,helping to maintain the correct and consistent composite-objectclassification.

The present disclosure thus provides inexpensive and compact LIDARsystems with enhanced object recognition, including an ability todistinguish material types, provide earlier detection and warningsystems, including an ability to identify an object within milliseconds,and high efficacy in low visibility conditions, among other benefits.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A system comprising: a laser configured togenerate a light pulse; a beam steerer configured to adjust apolarization of the light pulse to produce a polarization-adjusted lightpulse emitted towards an object; at least one polarizer configured topolarize reflected, scattered, or emitted light returned from theobject; and a processor configured to detect at least one material ofthe object based on an intensity and polarization of the polarizedreflected, scattered or emitted light from the object.
 2. The system ofclaim 1, wherein the beam steerer comprises a kirigami nanocomposite. 3.The system of claim 1, wherein the at least one polarizer comprises akirigami nanocomposite.
 4. The system of claim 1, wherein the processoris further configured to classify the object based on the detected atleast one material of the object.
 5. The system of claim 4, wherein theprocessor is configured to classify the object based on the detected atleast one material of the object by applying a machine-learningalgorithm.
 6. The system of claim 5, wherein the machine-learningalgorithm comprises an artificial neural network algorithm.
 7. Thesystem of claim 1, wherein the beam steerer is configured to adjust thepolarization of the light pulse by at least one of imparting apolarization to an unpolarized light pulse and changing a polarizationof a polarized light pulse.
 8. The system of claim 1, wherein the beamsteerer is configured to adjust the polarization of the light pulse byapplying at least one of the following types of polarization: linearpolarization, circular polarization, and elliptical polarization.
 9. Thesystem of claim 8, wherein applying linear polarization comprisesapplying at least one of s-type linear polarization and p-type linearpolarization.
 10. The system of claim 1, wherein the at least onepolarizer is configured to polarize the reflected, scattered, or emittedlight returned from the object by applying at least one of the followingtypes of polarization: linear polarization, circular polarization, andelliptical polarization.
 11. The system of claim 10, wherein theapplying is applying linear polarization that comprises applying atleast one of s-type linear polarization and p-type linear polarization.12. The system of claim 1, wherein the at least one polarizer comprisesa plurality of polarizers.
 13. The system of claim 1, furthercomprising: at least one polarization detector connected to the at leastone polarizer and the processor, wherein the at least one polarizationdetector is configured to detect the intensity of the polarizedreflected, scattered or emitted light from the object.
 14. The system ofclaim 13, wherein the at least one polarization detector comprises aplurality of polarization detectors.
 15. The system of claim 13, whereinthe at least one polarization detector is configured to detect an angleof incidence associated with the polarized reflected, scattered oremitted light from the object.
 16. The system of claim 15, wherein theprocessor is further configured to detect the at least one material ofthe object based on the angle of incidence associated with the polarizedreflected, scattered or emitted light from the object.
 17. A methodcomprising: generating a light pulse with a laser; adjusting apolarization of the light pulse with a beam steerer to produce apolarization-adjusted light pulse emitted towards an object; polarizing,with at least one polarizer, reflected, scattered, or emitted lightreturned from the object; and detecting, with a processor, at least onematerial of the object based on an intensity and polarization of thepolarized reflected, scattered or emitted light from the object.
 18. Themethod of claim 17, wherein the beam steerer comprises a kirigaminanocomposite.
 19. The method of claim 18, wherein the kirigaminanocomposite is manufactured via a vacuum-assisted filtration (VAF)process or a layer-by-layer (LBL) deposition process.
 20. The method ofclaim 17, further comprising: classifying the object based on thedetected at least one material of the object.
 21. The method of claim20, wherein classifying the object comprises classifying the object byapplying a machine-learning algorithm.
 22. The method of claim 21,wherein the machine-learning algorithm comprises an artificial neuralnetwork algorithm.